


Neurotoxin

by PresidentGuppy



Series: Neurotoxinverse [1]
Category: Gravity Falls
Genre: Almost Drowning, Blood, Choking, Fish Puns, Light Bondage, M/M, Mildly Dubious Consent, Other Additional Tags to Be Added, Teeth kink, Tentacle Sex, Tentacles, creature AU, octopus!Bill
Language: English
Status: Completed
Published: 2017-09-25
Updated: 2017-10-19
Packaged: 2019-01-05 08:19:14
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 8,237
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12186357
Author URL: https://archiveofourown.org/users/PresidentGuppy/pseuds/PresidentGuppy
Summary: “I’m,” his voice cracks, damnable thing. He never really could rely on his vocal chords when he needed them most. “—sorry?”There is a person attached to that writhing mass of darkness personified. It has a sly grin full of needle-teeth.It is a man.(For Billdip Week Day One: Creature Au)





	1. Approach

         Dipper is pretty sure there is a special ring in hell just for him.

         “An _author_?” There’s rustling in the sand, and noises that could only be described almost perversely as _slick_ and _wet. “_ How _…cute.”_

He thinks that circle in hell that is made for him is actually in the shape of a _triangle_.

         “I’m,” his voice cracks, damnable thing. He never really could rely on his vocal chords when he needed them most. “—sorry?”

         There is a _person_ attached to that writhing mass of darkness personified. It has a sly grin full of needle-teeth.

         It is a _man_.

         “What kind of writer are you?” Needle-teeth inquires. His voice is perfectly polite, if a bit loud in this echoing, _empty_ cove. Almost friendly, if one could squint at a sound.

         His visible eye glows gold.

         Dipper thinks this is what sirens are made of.

         “Do you like comedies?” the patterned creature continues when Dipper falters, fails to answer in his frozen awe. The slick noises continue, distracting. “Do you like a good _mystery_?”

         Tentacles—eight of them, he quickly counts, eyes twitching to each of the glowing triangles that line the ribbing—curl about the sand. He is not sure if his guest is prone to activity or just incapable of stopping, but the writhing of those _slickwetdark_ things makes him squirm in ways he is quite sure he shouldn’t voice.

         “Would you like to take a closer look?” The question is innocent, accompanied by an almost lazy blink. A stray arm squirms across the sand, tempting in its glow.

         Dipper thinks of poison.

         “I,” he starts. Coughs. “No, I—I would like to know what you are _doing_ here.”

         That golden eye seems sharp, as if it’s gaze could pierce right through his own much akin to a fish hook at the end of a lure. He is quiet, _expectant_.

         “— _Please_.” Dipper quickly blurts. He remembers manners, of his grand-uncle’s books telling of those lost to fae incensed by a lack thereof. “If it is of no trouble to you to answer, that is.”

         There’s a pearl of sweat rolling down his back.

         A pleased smile curls about the stranger’s face.

         “ _You_ ,” comes the pleasant reply, “I should hope.”

         Dipper’s book drops to the sand.

         “I’m _so-rry_?” he says, _again_ , his voice cracking in its high pitch. His cheeks flare red as the beast in front of him _laughs_ , horrifically loud. “ _What_?”

         “I’ve been keeping an _eye_ on you!” His question is ignored in favor of answers of a different kind. Those triangles seem to pulse blue, so quickly that Dipper wonders if he ever saw it at all. “Ever since you came here!”

         Dipper thinks back to five weeks ago, when in a fit of pique he moved to the coastline in order to find his muse after a year of _nothing_ in Piedmont. _Gravity Falls was an interesting town_ , his father had suggested. _You can stay with your Grunkle Stan for awhile. There’s all sorts of things that happen there!_

He’d been pacing the coastline’s coves and tide pools for the answer to his dilemma. A drama? A comedy? Folklore, mystery, _horror_? Completely unawares of his silent watcher from the sea.

         There were no people on the beach past six.

         He thinks he knows why.

         “I have something for you,” He’s charmingly excited about it, too. Worryingly so.

         Dipper is quite sure it is inappropriate.

         He wonders if it’s too late to run.

         “I can help you,” the creature has his book. _He has his book._ His notes crinkle as the almost-man flips through them idly, tracing the spine and corners almost lovingly. “How about a _deal_?”

         Dipper swallows heavily. He’s not entirely sure why, but he’s pretty sure that voice—dropping deeper, sonorous and hypnotizing— just prodded him in places he doesn’t really want to think about.

         He notes absently that those tentacles are steadily creeping closer.

         “What,” Dipper asks, cautiously, “ _kind_ of deal?”

         He then kicks himself, because this creature’s face lights up as if dinner had just been placed in front of him, all the fixings in place and ready to be devoured whole.

         “Oh,” his voice is a purr, pleasant and spine tingling all in one. Probably much like a neurotoxin. “just a little one. Not a _big_ _deal_.”

         He smiles winningly, and Dipper is torn between laughing along, relieved to find another so interested in wordplay as he, and maybe screaming in sheer terror at the brief flash of black gums.

         He settles on a slightly unnerved smirk, which seems to satiate the other.

“I can give you as much information as you could ever want about this place,” long fingers are tracing triangles into his notes, which Dipper thinks is odd mostly because he’s quite sure there are none in there to trace in the first place. It’s also a bit unfair, as those fingers looked quite dexterous and he was wondering just _how much, exactly, please. “Things you could never even imagine._ I can be a _muse_ to you.”

         Dipper glances at the sort-of-but-not-quite man’s face, flushing a rosy pink when he catches his eye. The thought _he knows_ is slightly overshadowed by the shrill _I could actually FINISH my novel!_

_“_ And in return, you…” Dipper coughs past the constriction of his throat as the other leers at him. He’s pretty sure that odd little wave of one of the smaller tentacles was supposed to be inviting. “Um. I don’t think we’re…That is, I don’t…I mean, you _know_ that I’m not a—“

         “Doesn’t matter,” comes the flippant reply, a relief from Dipper’s bumbling attempts at negotiation. He heart jumps as the other continues with, “I rather _prefer_ this way.”

         _He’s copying me_ , Dipper thinks, half affronted and half amused. Their conversation was utterly cyclical, dancing around the subject for, what, _his_ comfort?

         He’s oddly flattered. Slightly concerned that he was being manipulated, but that was the basis of _all_ human interaction, wasn’t it? This wasn’t so strange, his thinks as he eyes squirming appendages in the sand. Only a little bit.

_“_ The name’s Bill Cipher,” a wet finger delicately flips a page illustrating various starfish. “Do we have a deal?”

         “There is no way in hell that is your actual name,” Dipper blurts, incredulous.

         ‘Bill’ stares at him blankly.

         “Why not?” he asks, genuinely curious.

         “It’s just—“ Dipper tugs at the roots of his hair a bit, “I was expecting something, I don’t know, _foreign_. Like, like a _fish language_ or something _._ ”

         Bill’s mouth spasms, as if he’s trying not to smile. Dipper feels somewhat insulted. Mostly _stupid_.

         “I can’t be American?” his voice is slightly mocking. “I can’t speak English? In American waters? With a _dumb American name_?”

         “I get it,” Dipper grouses, embarrassed. He rubs at his eyes, then at an imaginary knot in his neck for good measure at the slow realization at where this conversation was inevitably headed. “I’m…Dipper Pines.”

         Bill is suspiciously quiet.

         “ _Don’t laugh_.”

         Bill says nothing at all. _Pointedly_.

         “…You can laugh a _little.”_ Dipper allows with a sigh.

         There’s a high pitched noise that could be interpreted as _painful_.

         “Are you _quite_ done?” Face aflame, Dipper kicks at the sand in aggravation. “Can I have my notes back? Can I _leave_?”

         “Do we have a _deal_?” comes the amused reply. Bill drums his fingers on the cover of his stolen prize, looking utterly pleased with himself.

         Dipper is tempted to say no. This strange being that had been stalking him for five weeks, half an octopus and probably as deadly, did not add up to a logical copulation.

         Although.

         _Killer autobiography_.

         “…You’ll help me with my novel?” The sand seemed quite interesting. Full of microscopic shells and rock. He kicks at it a bit, feeling rather shy. “…you won’t uh—actually, are you _poisonous_?”

         “No,” Bill says pleasantly. “Kindly don’t _eat_ me.”

         “I wasn’t—“ Dipper flushes at Bill’s vivid leer. A trap, god _damn it_. “Fine. _Venomous_?”

         “Only a little,” Bill says, innocent as you please. “I won’t _bite_. Unless you ask.”

         “ _Suspect_.” Dipper mutters under his breath, eyeing the other’s mouth with some trepidation. _Oral is out for that one,_ he thinks, somewhat relieved, before flushing to the roots of his hair at the thought.

         “ _Shy_ ,” the other coos.

         He decides to ignore that.

         “You can’t, uh, hypnotize me.” At Bill’s baffled look, he hastily continues, “Or drown me. Or kill me. Or maim. Or—“

         “Sheesh, kid, relax!” Bill’s laughing, incredulous and horrifically amused, the _bastard_. “I’m not a _siren_.”

         Dipper squints at him, wondering. Bill doesn’t elaborate on what he may or may not be.

         “Not a kid,” He says instead of asking, “I’m _twenty_. So…?”

         “I won’t hypnotize you,” he parrots, “or drown you. Or kill you. Or maim. Or whatever else going on in that pretty head of yours that doesn’t involve excessive _fucking_.”

         Dipper blinks rapidly, taken aback.

         Bill’s expression sours a bit, looking a bit embarrassed himself.

         Its oddly relieving.

         “…Deal.”

         Bill extends the hand not cradling Dipper’s notes with an enthusiastic flourish, utterly beaming from everywhere possible—eye and triangles included.

         Dipper stares at the proffered hand before he snorts. _What a business_ , he thinks, somewhat sardonic as he reaches over to take it. As if he had just aced an interview with a new employer. _Ha ha_. Welcome to Cephalopod Fucking Incorporated, please leave your clothes on the beach.

         The hand that takes his yanks him down to the sand.

         “ _No biting!_ ” He shrieks as Bill gleefully swarms over him to attach his mouth to Dipper’s neck.

         He is not wasting _any_ time, Dipper thinks somewhat dizzily as several dark tendrils creep under his clothes. The suction cups running along the underside of Bill’s tentacles attach to his skin and _hold_ with something akin to desperation. He doesn’t think he could escape even if he wanted to, not with Bill’s grip cinching steadily tighter about his legs.

         It’s a nice burn, he thinks dazedly. Kind of like rope.

         “I’m not!” Bill is squirming a bit, getting comfortable on his lap. It’s a bit difficult with how excitedly his tentacles thrash as they find better purchase on his skin, suckling violent rings of black-blue into the surface.

         Dipper is pretty sure he’s going to be having sand in unpleasant places for a very long time.

         Bill beams down at him, utterly pleased once he’s settled. Heavier than expected, Dipper wonders how he manages to swim when he’s so _dense._

         “I want your mouth,” he says.

         Dipper blinks at him.

         “Can I..?” those long fingers were tapping along his jaw, overeager. He finds it a bit gratifying, that Bill is so unabashedly eager to have him, in any way he could.

         “Ye—“ he’s cut off when Bill sticks several of those digits into his mouth so fast he nearly chokes on them. The other hand has a hard lock on his jaw, and he vaguely wonders if he’s going to be able to move at all in this bizarre affair of theirs.

         Unsure of what to do with his hands, he settles them curiously on Bill’s hips, thumbing the section where human skin seemed to blend into something a bit more rough.

         “Oh,” Bill breaths, the pads of his fingers tracing the ragged peaks of Dipper’s molars, “don’t see much of _these_.”

         Dipper isn’t entirely sure what he means, be it that molars are simply a rarity among fish (he wouldn’t know) or if he just didn’t smile enough (he wouldn’t know that, either). He doesn’t get a chance to ask; Bill has already moved on, his curious fingers wriggling deeper, in between his gums and his cheeks to prod the shy peaks of his wisdom teeth.

         He makes a sweet little moan when Dipper licks at his fingers, chases them across his teeth, and he flushes at the sound. He feels a bit like he’s melting, heat burning in his core to spread throughout his body wherever Bill touched. Full-body contact might kill him, he thinks as the other looms closer.

         Saliva is making trails down his chin, wet and warm. As odd as it feels to have someone tracing the backs of his teeth with their nails he finds it as soothing as he does arousing.

         “Soft,” Bill comments idly, toying with his tongue.

         A stray arm of black-gold slithers further up his shorts, the suction cups along the underside sticking to him in a near spastic delight. He knows already that he will be absolutely _covered_ in these odd circles that constitute as Bill’s affections, and feels strangely pleased about it. People would sooner think he’s had a fight with a octopus rather than a tryst with someone who was only half.

         He squints, politely ignoring the brief stab of pain when Bill hooks his fingers in the innermost wall of his jaw to tug his mouth open wider, excited and almost painfully curious to peer down his throat.

         Dipper wonders if he has a beak down there, hidden amongst his thrashing bonds, or perhaps something a bit more phallic, more _human_.

         He makes a strangled noise when Bill tries to shove his whole hand in.

         “Sorry,” he says, somewhat faintly as Dipper recoils for a chance to breath and maybe cough a bit. As if he wasn’t quite paying attention to his distress as he was transfixed by his _mouth_.

         “Is,” fingers creeping back towards his face pause as he swallows, “is it your _saliva_ that’s venomous?”

         “…Yes.” Bill’s mouth twists. “Salivary glands. Why?”

         Dipper scratches out the desire to kiss him. “Nothing.”

         Bill squints at him.

         “Do you,” Dipper absently strokes one of the tentacles surrounding his left thigh. It responds by tightening a notch, as if expecting him to try and pry it off. He might lose circulation in that one. “want to try, um—”

         “Not yet,” Bill says mildly. He seems eager to return to prodding at Dipper’s teeth, and far be it from Dipper not to indulge him, but—

         “ _Clothes_?” Sand was sticking to his shorts, his shirt, _damp_ and heavy from Bill’s thrashing. It was a bit uncomfortable—not that laying in the sand _without_ clothes wouldn’t be, but at least then he could get rid of the suffocating feel of wet denim off of his dick.

         Bill lets out an absent hum, considering him.

         The blood drains from his face when that gaze goes back to the sea.

         “ _No drowning_.”

         “I wasn’t _going_ to.” A whine, petulant. “It’s just _easier_. No sand. What about _choking_? Do you—“

         His brain momentarily short circuits at the mention of suffocation. It’s a struggle to get back on track. “Absolutely not.”

         Bill pouts at him.

         Dipper sighs through his nose, thinking.

         He’s not particularly interested in sand, either. Although the cove was closed for the night, leaving them to their devises uninterrupted, there really wasn’t a particularly good area for their intentions.

         He pauses, chasing a thought.

         This cove _was_ technically private property belonging to his great-uncle (who was undoubtedly laying in the shack sleeping through his favorite late-night drama). Under the pier was a section closer to the water, meaning—

         He glances at the shack, it’s form slanted slightly to the left as aways at the very end of the pier.

         “The pier is as close to the ocean as you _get_.”

         Bill blinks before following his gaze back to the water.

         “Oh,” he says, “I _see_.”

         Dipper nods, satisfied. “Alright, then get off—“

         He’s abruptly cut off when Bill decides that, rather relinquishing his grip, he’d rather just _drag_ his prize to the water.

         “Wait. Wait, _wait wait waitwaitwait—!”_ Saltwater floods his mouth as he’s dragged, thrashing, under. His eyes burn and he thinks, perhaps, that this was going to happen all along.

         Bill reaches the lowest platform of the pier just as Dipper is beginning to fade, hauling them both up in a terrifying display of dexterity.

         Dipper coughs, spitting saltwater as Bill, smug, twines his grip ever-tighter.

         “What the _fuck_ , Bill?!” He shrieks, horrified. “I could have _died_!”

         A snort. “I was there. It took two minutes.”

         Dipper coughs around the salt in his throat, struggling against the newly slickened appendages that were steadily creeping towards his hips. “Get _off_! That _hurt!”_

For a frightening moment, Dipper thinks that he won’t.

         Bill drops him.

         “Did it?” His voice is puzzled, as if the very idea of it is baffling to him.

         “ _Yes_ , it _did_ ,” Dipper bites out, squirming out of the nest of tentacles to curl up against the frayed rope that made up the safety fence of the pier, unable to stand on his somewhat numb limbs. Past the vivid, blinding anger he can see Bill wilting, recoiling to the point that he was condensed into a knot of black-grey-yellow.

         He tries to be understanding.

         He is _soaked_.

         “I can’t breath underwater like you can, Bill.” voice strained, he rubs at the bridge of his nose. He’s going to be smelling salt for a _long_ while. “I’m _human.”_

Bill seems to shrink a bit. He mutters something sounding suspiciously like _close_ that’s drowned by the waves below.

         “Do you get it?” Dipper frowns at the form across from him, wishing he could scrape his head out of the gutter. “No _swimming_. No _dragging_.”

         Bill makes an unhappy noise.

         Dipper gives him a hard frown.

         “I get it,” Bill grumbles. His appendages seem to be tying themselves in knots, oozing saltwater, significantly guiltier than their owner.

         Lips pressing into a thin line, Dipper sighs and rubs at his thighs where they had last gripped him, missing the feeling already. The mood was gone, leaving them with a cold tension he could cut with a knife. He gets the feeling that Bill wasn’t particularly prone to apologizing, and wonders if the other had anyone actually of the same species as him around at all.

         Given what he knows about octopus, he’s thinking that’s a small _no_.

         “That’s not an apology,” Dipper settles against the rope, absently toying with his soaked shirt, an idea blooming against his oxygen-deprived headache.

         Bill gives him a sullen look.

         “You _know_ how to apologize,” Dipper continues innocently, tugging his shirt collar lower to expose the bruise Bill had sucked into his skin earlier, enticing, “ _don’t_ you, Bill?”

         The triangles scattered across Bill’s appendages flairs a brilliant, blinding blue.

         “ _Oh_ ,” he coos, eye alight. The boards of the pier creak under his weight as he crawls towards Dipper, a vision in blue light and dark skin.

         Dipper’s a bit terrified, if he’s perfectly honest.

         Good thing he _isn’t_.


	2. Temporary

Dipper wonders absently where Bill came from. Was he native to Gravity Falls’ coastline? Did he have a family, somewhere? Anywhere?

         Bill was tugging on his flannel jacket, rolling it off his arms with a pleased little murmur. It was hard to imagine, but he seemed almost _touch-starved,_ wrapping himself about Dipper’s body so tightly as if to say that he would never let go. As if frightened he would disappear if left to his own devices.

         Teeth lightly graze his bare shoulder. His pulse jumps—venemous, poisonous, _paralysis_ —before Bill moves elsewhere, trailing feather-light kisses across his skin. He doesn’t sink his teeth in, doesn’t bite, though in the back of his head Dipper almost wishes he could.

         He’s not entirely sure the level of toxicity of Bill’s venom but given his general size Dipper was willing to bet it would kill him _instantly,_ whatever kind of venom it was.

         He probably shouldn’t be as turned on at the thought as he was.

         Bill gives him just enough room to shrug off his wet t-shirt before he’s back to invading his personal space, trailing delicate fingertips down his chest, tracing his collarbones and ribs with something akin to awe. He digs his nails in just over his fluttering heart, as if he would like to tear it out and keep it for himself, and Dipper can’t entirely fault him for leaving tiny crescent shaped marks behind.

         Dipper idly traces Bill’s ribs as he’s distracted, marveling at the small slits the constitute his gills. They’re small, almost unnoticeable if one ignored the wavy membranes flaring from within, gold and glitteringly wet. They twitch under his fingertips, butterfly-light.

         “So _curious_ ,” Bill mumbles into his collarbone, shuddering when he traces the slit of the largest.

         “And you aren’t?” Dipper snorts, amused. Then, softly, “ _Sensitive_?”

         “ _Very_ ,” comes the breathy reply. Bill’s nails catch in his skin as he drags them down, eager and sickly sweet.

         Dipper’s breath hitches when he grazes his nipples, pausing to circle them curiously with calloused thumbs as they harden. He realizes, somewhat belatedly, that Bill didn’t have _any,_ and wonders if Bill was ticking off their differences in his head much like he was. A mental checklist on their compatibility, how well they could slot together. 

         “Um,” Dipper prompts as Bill tugs on one, interested. Heat flares down, and he momentarily loses his thought when the other leans over to _lick_.

         “Bill? _Ah_ ,” he’s tugging on a stiffening nub with one hand as he sucks the other, and Dipper can’t quite get his words together when he glances up to lock their eyes, delight written all over his face.

         “ _Ye-es_?” Bill releases him with a wet _pop_. His other hand is wandering down the planes of Dipper’s stomach, raising gooseflesh in it’s wake. He digs his nails in to scratch just over his belly, toying with the fine hairs that grow in thickness steadily downward. 

         He has to take a moment to catch his breath, raising his hands to tentatively wrap them about Bill’s elbows. He doesn’t want to stop him, not at all, but Dipper wasn’t particularly known for his stamina. The pulsing between his legs is a delicious warning and he has to curb it before he comes, embarrassingly, in his jeans.

         Bill, patiently, keeps toying with his skin in the meantime. He is terrifically amused, watching Dipper’s face with a mix of eagerness and delight as he pinches fat and prods muscle.

         “Do you do this _often_?” He finally bites out, squirming under idle fingers, scarlet in every sense of the word, “I mean, aren’t there other, uh, whatever-you-ares out there? Why _me_ , in particular?”

         Bill pauses.

         “… _if you don’t mind me asking._ ” Dipper cringes. He regrets opening his mouth already, and he hasn’t even _said_ anything in reply yet.

         “Hm,” Bill says, eyeing him cryptically.

         Dipper sweats a bit.

         “No, also no, and because I _like you_.” a tentacle was breaching the space between his legs, curiously tracing the outline of his crotch. “You’re a funny one, kid. Talking to yourself in the middle of the night, pacing my coastline. _You never went into the water_.”

         Dipper lets out a strangled moan when Bill pops the button on his jeans, impatient at last. Hooking his fingers into the belt loops to better drag them down his thighs, Bill revels in his tan lines and stretch marks. He traces them lightly with his nails as he grins.

         “I’d hear you walking the pier, I’d _see_ you dangling your legs over the sides but you were always _just out of reach_.”

         Bill toys with the hem of his briefs, soothing the space between fabric and skin with delicate fingers, eye zeroed in at the bulge straining under the fabric. Dipper is torn between shucking them himself and settling further into his bonds, wavering in heat under his intense gaze. He can’t lose them completely, not with the tentacles in the way, and feels that much more trapped in Bill’s embrace.

         Like a bird in a cage. Like _prey_.

         “ _Pretty boy_ ,” Bill coos at the sight, “ _I want to eat you alive_.”

         Dipper whimpers, jerks against his bonds. His heart is lodged in his throat, an almost animalistic panic running up his spine and setting his nerves alight. He’s terrified yet he’s never been so turned on in his _life;_ the whiplash Bill is giving him is going to drive him insane.

         Bill chuckles darkly, sliding his briefs down agonizingly slow, his grip tight. His eye lights up at the sight of his dick, curved towards his belly and twitching in wanting.

         “W-wai-!” Dipper’s plead rises to a screech when Bill wraps the tapered end of one tentacle around his dick and _contracts_. The suction cups—smaller than the rest, innumerable and slick—leave trails of false kisses along the length, making him shudder violently. He can’t—not when it’s wound that _tightly_ —

         It’s different from the rest, he realizes as the spearheaded tip lines up with his own. He can feel it pulsing all the way around, a maddening vein like a web curling about his length to tease. _Why the hell is it different from the rest?_

_“Do you like it?”_ Bill has his hands on his jaw again, is pulling at his skin to reveal pearls and gums. “ _I like yours_.”

         “Bill,” Dipper grits through his teeth, past the fear lodged in his throat, “You _can’t_ —“

         “‘I know,” Bill’s grip seems to tighten about his legs while his hold on his dick lessens to a soothing caress, focusing instead on gentle, almost _teasing_ undulations. The sound alone was enough so send him to the edge, slick and so, _so_ wet. “I’m just—“ His breath hitches when Dipper sucks on his fingers, tongues the webbing between, tasting salt. “—c _urious_.”

         The tentacles around his thighs keep him grounded, keep him from rutting up to disturb Bill’s pace. His legs are almost entirely hidden under Bill’s skirt of thrashing bonds, and the spares toy with his sack and trace maddening triangles about his perineum, leaving warm slick in their wake. Bill’s phallus is steadily oozing pre over his own, mixing them with every wave and making him twitch.

         Dipper moans around the digits in his mouth as Bill continues, his glowing eye drinking him in with greed and labored breath. _Must be a sight to see_ , he thinks dizzily, squirming just enough to thrust once into Bill’s coil before he’s pressed lovingly back down to creaking floorboards, scraping his back with loose splinters.

         He wants, viciously, for Bill to take him. To grind him into the floor, to bend him in _half_ , squeezing the life out of him one centimeter at a time.

         He wants Bill to kiss him.

         Dipper gags around the fingers squirming eagerly towards the back of his throat, pressing on his tongue and knocking on his teeth. Bill only gives him a moment to catch his breath before he’s trying again, unabashedly eager and contracting tightly around his dick every time he chokes.

         He should probably be concerned about Bill’s titillation in choking him with his fingers, but the fact of the matter was that he’d been doing the same thing to himself since he was sixteen, lonely and horny beyond measure, so this wasn’t so strange in comparison now _was it_?

         Bill was getting further than he’d ever had on his own, fingers curling around his tongue to press and prod at the walls of his throat. He’s not entirely sure if Bill wants him to choke on purpose or if he was just trying to see how far along, exactly, he could force himself in.

         When Dipper finally whines in protest— _enough, I can’t, just wait—_ Bill takes his spit-flecked fingers and, trailing thick strands of Dippers saliva in a bridge that connects them both, shoves them into his own mouth with a heady moan. It’s as close to a kiss Bill could ever get from him, and the thought of it makes him sob with need, jerking up to sink his teeth in the meat of Bill’s shoulder.

         To leave a mark, _any_ kind of sign, that he’d been there.

         That he’d been _loved_.

         Bill groans around his fingers, his head dropping to press his forehead insistently to Dipper’s collarbone. His teeth sink further into Bill’s skin, adoringly slow, pressing past indentations and breaking into the blood vessels below as the other muffles his keens.

         The mark left behind—a near perfect ring of tooth marks, slightly oozing blood- made his heart spark with pleasure. He likens them to the ringed bruises littering his own body and feels settled. _A matching pair,_ perfect in design.

         Dipper gives him two more before Bill manages to pry him off, gasping and shuddering so clumsily that his grip loosens.

         “I want—“ Bill lets out a strangled moan when Dipper claws at his back and ruts into his coil, desperate. “ _I want to taste you_.”

         Dipper shudders in turn. “ _Yes,_ ” he whimpers, desperate. For his release, for _Bill_.

         He doesn’t think he’s wanted someone so badly in his entire _life_.

         He sobs when Bill’s tentacle leaves his length, suction cups leaving farewell kisses along his vein as they go. He’s pulsing to the rapid fluttering of his own heart and he doesn’t have very long left in him—

         It’s replaced with Bill’s hand, steadying him so that his tip lays flat on Bill’s tongue, swathed in wet gold and bracketed by silver needles.

         Dipper _wails._

He spasms through his orgasm, held so tightly that he can’t jerk any further into Bill’s mouth, his tongue, his _teeth._ Eyes rolling into the back of his head, he chokes on a sob as Bill presses his tongue flat against him to gather every drop, moan vibrating past his head as ropes of white spill from his tip in pulsing bursts.

         He’s gasping for air like he’s dying for it, slowly winding down from his temporary high to settle back on the ground from where he had bent his spine near in two, shuddering and sensitive.

Past the haze clouding his head he can see his come collect and pool in Bill’s mouth, oozing past his lips and dribbling down his chin in thick, sticky droplets. His lower half is still pulsing with those sweet aftershocks, leaving him reeling and disconnected from reality, thinking that the other really does have such a nice _mouth_.

         “ _Oh_ ,” he gasps as Bill opens his jaws wider for him to see, come trickling down his chin to drip down onto his spent cock below. 

         Dipper raises trembling hands to caress the sides of Bill’s face, to bury his fingers in his hair when he—

         _drags—_

Bill forward, surges up to meet him as he sucks his tongue into his mouth to taste himself on his teeth, to press wet lips against his own and _moan_ , long and loud. It’s salt and something undefinably organic, _heady_ and sticky on his tongue as it spills between them.

         He swallows what he gets, saliva and come tacky in his throat.

         Bill stiffens against him, jerks backwards with a distressed sort of whine, but with Dipper’s hands tangled in his hair he is followed, tongue pressing against his sharp teeth, prodding at his gums and the roof of his mouth. He presses his hands against the other’s chest, his shoulders, his jaw, trying to pry him off. A warning, a plea.

         Dipper crowds closer, kisses him until his lips numb, until his jaw stiffens and he’s slurring mad coos against Bill’s lips. He twists to press ever closer, dragging Bill’s lower lip into his mouth to suck and gnaw on, delighting in his hitched breath and soft cries, pleasantly warm in his adoration.

         His mouth is buzzing as if full of static and his movements turn clumsy, confused. He licks along Bill’s mouth and feels _nothing_ , as if he wasn’t there at all.

         For a soft moment Bill kisses him back, strokes his cheek and tugs on his hair to tilt his head, to slot them better together when he no longer can, breath becoming labored through his nose to accommodate Bill’s suffocating affection, to fight against the weight suddenly bearing down on his lungs.

         Dipper winds closer, excited, as if he would rather meld them together rather than part, and Bill _bites his tongue._

He recoils with a yelp, blood spilling past his lips and flooding his mouth with the horrific tang of iron.

         “Bi-ll…?” Dipper croaks, _slurs_ past the numbness in his mouth. His eyelids are oddly heavy, and he can’t particularly feel his face. Drool and blood spill from his mouth, unnoticed until it drips onto his chest.

         Bill looks stricken, _horrified_.

_“Don’t_ ,” his breath hitches, “ _don’t move._ ”

         “Why?” It’s rough, trying to get his jaw to work when he can’t feel it. “I— _Oh_.”

         “It’s worse,” Bill croaks, skin rapidly paling, “if you _move_.”

         For a fraught moment, they stare at each other.

         Dipper, now past his blissful haze, could feel the numbness spreading from his face down, towards his chest, his _diaphragm._ Shutting off his nerves one by one like lights blinking out of the night sky. His heart drops in terror at the realization.

         “ _Stay here_ ,” Bill blurts, scrambling to untangle himself from Dipper’s legs. He has to force one off himself when it curls stubbornly around Dipper’s ankle, and through his panic he’s babbling, “ _I know what to do just lay down and **don’t panic**_ **—“**

         “Bill?” Dipper wobbles, catches himself when the other nearly knocks him over in his haste to get away. He presses his fist to his chest, to his lungs, wondering how the hell he hadn’t noticed it ever being _this difficult to breathe_ —

         Bill wavers, just at the edge of his vision. A hand, trembling, presses against his sternum, just over his closed fist. “I’ll be _right back_ ,” he presses down, insistent, when Dipper struggles against him, voice of protest caught in his paralyzed throat, “we have a _deal_ , remember?”

         Dipper feels cold.

         One last press and then he’s—

         “ _Don’t go_ ,” he forces out in a dry rasp. His heart convulses in his chest, as if trying to fight its way out, away from the venom steadily making its way through his body.

         He drags in a stuttered breath, feeling light headed. Darkness crowds his sight and he shudders in panic and fear. He shuts his eyes against the blurring sky.

         He wishes he could regret it.

 

 

 

 

 

 

**Notes for the Chapter:**

> Posting this really quick before I go to class okay BYEEEEEE


	3. Permanent

         When Dipper wakes up, its to distant thunder.

         He’s half-buried in several quilts he vaguely remembers Mabel buying for him before he had left Piedmont, propped up just enough that he could observe the dim lab with relative ease.

         The lab.

         _Great-Uncle Ford’s lab._

He struggles to sit up a bit more attentively, eyes widening. He’d only seen it once, when his Grunkle Stan had given him the home tour upon his arrival. Ford had quickly shooed them out again, citing delicate work, but not before Dipper had gotten a glimpse of jars full of dead jellyfish and mutated sea slugs.

         _Marine biologist_ , Stan had said, rolling his eyes. _More like mad scientist. Hah!_

It was roughly the same as he had last seen it; the walls littered with diagrams and nautical maps, jars lining shelves and filing cabinets, a desk in the corner covered in tools and an old computer that he was pretty sure hadn’t worked in years judging by the dust and cobwebs.

         There’s another door, closed, opposite the couch Dipper was seated on. This he knew lead to the staircase leading to the rest of the house.

         Meaning the door at the foot of the couch lead…

         “I’m not angry,” Stanford Pines says, peering out from the door leading further in his lab. He fully enters the room bearing a tray of sandwiches and what looked like orange juice, walking over to set it on the table next to Dipper. His coat is covered in black blotches, small blooms of dark stains. “I’m just a _bit_ disappointed, Dipper.”

         Dipper blinks at him, refrains from burrowing deeper into his quilts in confused shame. “Uh. What _for_?”

         Ford frowns at him over his glasses. Then, reaching over to feel Dipper’s forehead with one six-fingered hand, says somewhat unhappily, “I suppose you wouldn’t remember right away. Tetrodotoxin has…damaging effects on the mind.”

         “ _What_?”

         Ford sits on a nearby footrest with a gusty sigh and says, “Kid, you were officially dead for a _minute_.”

         Dipper’s jaw drops. “I was _dead_?”

         “For a minute, yes.” Ford squints at him before scooting the sandwich tray closer to him, the command clear.

         Dipper shoves half of one in his mouth impatiently and then says, spraying crumbs on the quilt, “ _Why_?”

         Ford examines him closely, looking reluctant.

         “Well,” he says.

         Then, again.

         “ _Well_.” He rubs at his face with one hand. He seemed almost _embarrassed_. “Perhaps _seeing_ him would be better.”

         Dipper quickly shoves the other half of his sandwich in his mouth, impatient. Who was Ford talking about? His brain a fog, he struggles out of his blankets. There’s at least _three of_ them, embroidered with little cartoon stars and constellations, and he’s pretty sure the ratty flannel one belonged to Stan, personally.

         He had died, yet he felt perfectly _fine_ , if a bit groggy. Maybe a bit sore, as if he was covered in bruises.

         Looking down at himself, he doesn’t see much past his long flannel pajamas and cotton tee. 

         He tried to think back. His last memory; pacing the cove, the beach, avoiding the water lest he drop his notes in it. The day had been reaching its end, _had_ ended, and then…

         Dipper follows Ford deeper into the lab, scratching at his head in his confusion.

         More shelves of jars, of diagrams and skeletal models of fish. There’s a podium with a thick tome on top, a table lined with chemistry equipment, and a stool that looked ready to fall apart at the slightest breeze. His bare feet are frozen to the floor, because there, at the end of the room taking up the furthest wall in its complete entirety was….

         “Oh god _damn_ it.”

         Nothing.

         A fish tank, rectangular in shape and completely filled with black, brackish water, as if it were a void in space as opposed to a container for sea life. There wasn’t a single fish to be seen in it, if there was anything in there at all, and the water was completely, _unnaturally_ still.

         Its lid was on the floor amongst smears of wet grey.

         “He keeps trying to get into my _fridge_ ,” Ford is grumbling, rubbing at the space where his glasses met his nose. “That _awful_ creature. Stay here while I get him, and try not to _touch_ anything.”

         Ford leaves the room with one final sweep of his trench coat, still muttering to himself.

         Dipper frowns at the closed door. Then, at the tank.

         What was he, _twelve_? He was completely capable of _not_ touching things. He’s pretty sure, in fact, that he’d rather touch nothing at all.

         Absolutely… _nothing_.

         He plods around the black-grey puddles and half-soaked diagrams to stare into the void. Light didn’t reflect from the glass, he was interested to note; the darkness within seemed to drink it in, leaving behind nothing but a black wall. He couldn’t see his reflection in the tank. He couldn’t see _anything_ , peering in from the side.

         He squints and tilts his head to and fro, but sees nothing. No movement, no fish, no odd specs of light vaguely resembling triangles…

         Dipper blinks. Peers closer, pressing his forehead to the glass.

         Was that… _movement_?

         Dipper looks around, Ford’s name on his tongue before he pauses.

         There was a small step ladder next to the tank, unused and clean.

         _Inviting_ , even.

         He kicks it a bit closer to the tank before he climbs it to peer in from the open top, a familiar feeling wriggling in the back of his skull, pinching his nerves. The water smelled heavily of salt, more so than the ocean just outside, and had the surface of a clear plane of glass.

         Unnaturally, _dangerously_ still.

         There was _something_ _in there._

         Curious, hesitant, with familiarity ringing terror bells in his skull, he touches the surface of the nothing with one hand.

         A single ripple flutters from his palm to the corners of the tank but _doesn’t return to make more._

         It’s freezing cold, yet delicately buoyant. It takes a bit more effort than he’d thought to force his hand an inch deep, until his wrist was covered and he easily lost sight of his fingertips. Thick and wet, yet not gelatinous. He wonders at the salt content, and thinks that it may be in fact a bit _too_ much to support any kind of sea life.

         He wishes he had his notebook. He’s…not entirely sure where it went, now that he was thinking about it. He’s terrified but morbidly curious of this strange void; he likens it to the reaches of space, to a shadow-infested realm, to something _beyond_ human understanding.

         Riveting. _Inspiring_.

         A memory curls against the waves of his grey matter, scratches at his blood and whispers nonsense. He knows this, he thinks. He _knew_ this, somehow.

         Something brushes against his middle finger, delicately light.

         _Slimy._

Dipper jerks back, startled. The step-ladder creaks in warning but continues to hold his (not inconsiderable, _thank you very much Mabel_ ,) weight.

         He stares in frozen fear. The water hadn’t changed; not a single ripple to tell that something had moved within, that something had _approached_ him, _touched_ him.

         It hadn’t hurt.

         A ghost of a feeling, of a memory. He thinks he remembers that particular ridge, that slick something-or-other.

         Ford hasn’t come back yet. Dipper can hear him puttering up the stairs, one at a time on his bad knee that was worse in bad weather. He had time. Plenty of it, in fact.

         He dips his hand back in, slow.

         Tempting.

         There’s less hesitation. That slick thing curls amongst his fingers, creeps around his wrist and breaches the surface of the water to wrap around his forearm. It’s as dark as the water, with suction cups on the underside that stick to his skin like timid kisses.

         He thinks of rope just as he’s dragged into the void.

         The cold water is a slap to the face, but despite the sting his eyes are wide open because amongst plumes of ink and salt was _Bill_ , illuminated in gold with his face stretched into a terrifying but familiar needle-teeth grin.

         Bill.

         Bill!

         Dipper’s heart rockets into his throat; the memory of meeting him, of their affair along the coast, on the pier—

         of _dying_ —

         He flinches, abruptly terrified. Ashamed. The one thing he wasn’t supposed to do, that he _shouldn’t_ have done…

         Bill had tried to warn him. Had _tried_ to stop him but he; delirious, giddy, _stupid_ , had kissed him anyways.

         Hands rest against his cheeks, trace his jawline in feather-light motions. He peeks at Bill’s face and finds it softer around the edges than before, sweeter and a bit anxious. He had been worried, _frantic_ when Dipper had fallen.

         He had found Stanford; for help.

         The image makes his mouth twitch into a smile; Bill prying Ford’s lab window open, startling the man out of a nap or mid-dissertation. Of Bill pleading for help from a man three inches from a decorative harpoon and an open tank of dead jellyfish.

         Bill mirrors his expression. He’s not entirely sure he likes it, this timid affection. This quiet fear, muffled with uncertainty. As if he feared rejection, even now, despite the fact that Dipper was now securely cinched in his steadily tightening grip.

         Thin fingers sweep up his jaw to tangle in his hair, floating oddly in the new eddies made by Bill’s thrashing. He’d been completely still before Dipper had joined him in the tank but now he was steadily increasing his own momentum, the tentacles not holding Dipper in place curling about themselves as if to sooth energetic nerves. _Too soon_ , they seem to say. _Not yet._

His lungs burn. His eyes too, because someone wanted him so badly that they feared his rejection, _changed_ in their desperation to something hesitant and shy.

         He hated it.

         It wasn’t like Bill, not at all.

The blots consisting of his birthmark are traced in reverent affection. His namesake, a curse he has long since tried to reclaim, is grazed from _Alkaid_ to _Merak_ in gentle sweeps of adoration.

         A single kiss, gentle and chaste, is pressed to _Megrez_.

         Bubbles fly from his open mouth as he gags on salt and ink. Startled from bittersweet rumination, he jerks in Bill’s hold. They’ve barely been under for a minute but he was already out of oxygen.

         Bill doesn’t let go. He looks, contentedly, like he’d rather keep Dipper under the water with him forever. His limbs tighten around Dipper’s form, suffocating.

         He swims upward.

         Bill gives Dipper just enough room so that they breach the surface of the water together, so that he can cough the tar from his lungs unimpeded as Bill watched, lone eye glinting oddly. He’s unusually quiet, though he still pets Dipper’s chest and bared arms as he gasps, dragging in deep lungfuls of air.

         “Bi-ill,” Dipper croaks, agonized. Bill had kissed his birthmark. His ugly, awful, _horrific—_

         There’s an enraged shout full of violent expletives, and quite suddenly there are six-fingered hands bruising his arms in order to haul him out of the tank.

         Dipper, voice rusted from salt, makes a feeble protest.

         A solid _thud_ shudders the tank as Bill attaches himself to the side, still wrapped securely around Dipper’s waist and legs. He says nothing, glowering past Dippers collarbones at the intruder, his eye flashing red-blue in clear warning.

         “The deal is _off_ , Cipher!” Ford growls with a fruitless yank on Dipper’s sodden T-shirt. “He died for a _minute_ he is no longer under your jurisdiction!”

         Dipper opens his mouth to protest— _what jurisdiction, its not like he signed a contract or anything_ —before he’s interrupted by Bill’s growl somewhere by his throat.

         “He’s still _alive_ ,” tentacles wrap ever tighter around Dipper’s legs and he warms in remembrance, cheeks pinking as his captor continued, “so it still _counts_. He’s not dead until his soul leaves his _corpse_.”

         Dipper thinks that he may be missing something, here.

         “ _Great Uncle Ford it’s not a big deal_ ,” he wheezes as Bill’s tentacles creep further up his thighs. The distressed almost-human was steadily inching his way up Dipper’s frame, _squeezing_ everything he runs across as he climbed, and Dipper’s pretty sure he would die of sheer embarrassment if he got a boner in his great uncle’s fish tank.

         “ _Not a big deal_?” Ford outright snarls. He doesn’t let go, despite the fact that Bill was baring his teeth awfully close to his skin. “ _You sold your **soul** to a **leviathan** for a **novel**!_ ”

         Dipper blinks. Swivels his head to look at his great uncle in bafflement. Wriggles his pinky in his still-water clogged ear and says, voice somewhat faint, “He’s a _what_?”

         Stanford lets out a pained noise. Dipper pities him for about five seconds before he rounds on Bill, who was sniggering into his chest, his tentacles thrashing and glowing in his malformed glee.

         _Huh_.

         “…I thought leviathans were supposed to be bigger?”

         Bill stops laughing long enough to leer at him.

         “He’s still _young_ ,” Ford says loudly, drowning out whatever lewd comment Bill had opened his maw to make. Bill pouts as he continues, his grip on Dipper slacking somewhat in recognition of a pointless war,“—well. Young in _leviathan_ terms. He’s several _thousands_ of years old but is still considered a _reckless teenager_ in their farce of a culture. He gets bigger eventually.”

         Dipper squints. Recalls being called _kid_ and thinks that maybe he should have seen this coming.

         Bill’s limbs squeeze just above his knees; despite his smug glare directed at Stanford he’s still full of that quiet anxiety, as if Dipper was going to protest his attachment despite their deal being brought to light as decidedly permanent.

         At least, he _thinks_ it is.

         (He hopes it is.)

         “How big?” Dipper prompts, trying to sound casual and failing spectacularly. The thought of Bill growing to the size of a cruise liner hiding in a deep sea trench made him shudder in a way that wasn’t entirely unpleasant. A bit intrigued, actually. He wondered how it would work; if Bill would grow more limbs, change color, or shape.

         He reaches into the brackish water to give the limb wrapped around his left thigh a gentle stroke as he thinks.

         “Enough to eat solar systems,” Bill inches closer with a small shudder. Then, quietly at Dipper’s throat, his voice husky, “‘ _Could eat you, if I wanted_.”

         Dipper flushes at the small kiss placed over his throat. Startles slightly at the recognition and says, voice coy, “Kindly don’t _eat_ me.”

         Bill grins, baring silver needles.

         “If you’re going to be doing _that_ ,” Ford interrupts, voice clipped and still very much there, “then _get out of my tank._ ”

         “Er, sorry, Great Uncle Ford—” Dipper flushes scarlet as said uncle at last releases him to step back down to the floor, grumbling all the while. “We’ll get out, I promise!”

         Bill slips an idle hand under his now loose tee with a crooked grin and he thinks _maybe_. _Eventually. Possibly._

_“Did you know_ ,” Bill whispers softly, voice a gentle lull just for him, “ _that repeated doses grant immunity_?”

         Dipper isn’t entirely sure he wants a repeat of his brush with death, of having to be revived by an irate great uncle _again_ , but…

         _He really does_ _have such a nice **mouth**_.

**Notes for the Chapter:**

> The end!!! I might come back for more anecdotal nonsense for this, however. Who knows.


End file.
